Rotatable Substrate Printing Using Polar Grid Mapping for Uniform Deposition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing apparatuses for applying flowable materials onto a rotatable substrate suffer from geometric distortions, inhomogeneities, and slow printing speeds due to complex structures and many small printing heads, making high-quality and homogeneous printing challenging.
Innovation Solution
The use of a second memory to store special polar coordinate grid points arranged on circles with predetermined circumferential distances and angular distances, allowing for transformation into a Cartesian coordinate system to ensure uniform material distribution and precise nozzle control for consistent image density across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If printing head arrangements are displaceably arranged over a circular-ring-shaped substrate in the radial direction, then material can be applied to the substrate, but the path length difference between inner and outer circles causes inhomogeneous material density
Solution Approach 1:
The patent transforms the coordinate system from Cartesian to polar coordinates, fundamentally changing the mathematical parameters used for positioning and controlling the printing heads. This parameter transformation allows the system to naturally accommodate the circular geometry of the substrate, ensuring uniform material distribution without complex mechanical adjustments.
Solution Approach 2:
Instead of moving the printing heads radially over a circular substrate (traditional approach), the patent inverts the approach by keeping the printing heads stationary and rotating the substrate. This inversion simplifies the mechanical structure while achieving the same printing function with improved uniformity.
2Area of stationary object
If many small printing heads are used to cover the circular substrate, then material application is possible, but stitching becomes practically impossible and geometric distortions occur
Solution Approach 1:
The patent employs a single printing head that performs multiple functions by printing different sections of the circular substrate during different rotational positions. This universal printing head replaces multiple specialized printing heads, eliminating stitching issues while maintaining full substrate coverage capability.
3Adaptability or versatility
If printing head arrangements are displaceable over the substrate, then material application flexibility is achieved, but printing speed decreases due to displacement time
Solution Approach 1:
The patent inverts the traditional approach by making the substrate movable (rotatable) while keeping the printing head stationary. This inversion eliminates the time-consuming radial displacement of printing heads while maintaining the flexibility to print anywhere on the circular substrate through coordinated rotation and radial positioning.
4Speed
If the inner circle path is shorter than the outer circle path, then printing is faster at the inner circle, but material density becomes non-uniform across the substrate
Solution Approach 1:
The patent changes the control parameters from linear Cartesian coordinates to angular polar coordinates, allowing the system to compensate for the varying path lengths at different radii. By controlling the angular position and rotation speed, the system maintains uniform material density while accommodating the natural speed variations inherent in circular motion.
Data Source
AI summary
The invention relates to a device for applying flowable material to a substratum (3), which can be rotated about an axis of rotation (4), in accordance with specified image data, which are stored as pixels or as vectors of a certain Cartesian coordinate grid in a first memory (18), has at least one printing head (13A, 13B), which has a plurality of nozzles arranged at a nozzle distance from each other for discharging material drops of the flowable material and is arranged at a vertical distance from the substratum, and a controller (8) for positioning the substratum (3) in relation to the at least one printing head (13A, 13B) and the discharge of the material drops. In a second memory (19), particular polar coordinate grid points (20A, 20B) of a certain polar coordinate grid are stored, which polar coordinate grid points are arranged on circular lines (R1, R2) having a predetermined circular-line distance from each other and are arranged on first rays (A1), which have a first angular distance from each other and are arranged in the direction of origin on further rays (A2) having an angular distance from each other that is greater than the first angular distance. A computer (15) is present, by means of which the particular polar coordinate grid points (20A, 20B) stored in the second memory (19) can be transformed into coordinates of the certain Cartesian coordinate system and the Cartesian grid points thus obtained are compared with the pixels of the image file.